An artificial tooth is a dental material used by an odontologist or a dental technician in the production of a denture having a base plate. Among the artificial teeth ranging in different sizes and shapes, a tooth suitable for a patient's missing tooth and a therapeutic approach is chosen and used.
To produce the artificial tooth, a patient's intraoral counterdie is formed from an impression material and plaster is poured into the counterdie and then hardened to make a model. The model is then mounted on a device for replicating gnathic motion, called an articulator, to perform a work on the model.
Examples of the articulator are an adjustable articulator in which guide path angles of joint articulations in lateral movements of the denture can be adjustably set, and a mean value articulator in which these angles are set to mean angles of human. In the case where an odontologist determines that any particular angle adjustments are unnecessary, the mean value articulator is used.
In prosthodontic treatment using a complete denture, it is desirable to accomplish an occlusal state, generally called, bilateral balanced occlusion. There are two types of bilateral balanced occlusion, full-balanced occlusion and balanced occlusion. The full-balanced occlusion denotes an occlusal relation where all of teeth simultaneously make contacts in intercuspation and in all of eccentric movements. Clinically, however, the replication is quite difficult due to, for example, errors generated in alignment and grinding adjustment, which leaves the balanced occlusion as a practical option. The balanced occlusion denotes an occlusal relation where several teeth may not make any contact as far as there is gliding motility in two or three teeth on a working side and two or three teeth on a balancing side in the eccentric movements. According to the balanced occlusion, therefore, a denture adapted to mandibular movements, which is different in each patient, can be produced through preliminary grinding adjustment during the production of the denture followed by final adjustments by the odontologist made on the denture intraorally worn by the patient. The working side denotes a side where the row of mandibular teeth shifts to a buccal side relative to the row of maxillary teeth in the lateral movements, and the balancing side denotes a side opposite thereto. When upper and lower jaws are making an occlusal contact and the lower jaw is then moved, for example, the working side is on right, and the balancing side is on left.
In the Patent Document 1, the present Applicant has proposed artificial teeth wherein a relative positional relation between cuspis dentis and fossete is defined.
The manipulation to enable the bilateral balanced occlusion through the grinding adjustment is a very time-consuming and demanding precision work. Therefore, an artificial tooth ground beforehand into a shape in accord with the motility of the mean value articulator was a long-awaited product in the field of odontologistry.
Patent Document 1: JP Laid-Open Patent Publication 2003-102752